In this P01, we will pool data, samples and expertise from 4 of the largest studies of breast cancer in AA women, the Carolina Breast Cancer Study (CBCS), the Women's Circle of Health Study (WCHS), the Black Women's Health Study (BWHS), and the Multi-Ethnic Cohort (MEC). We will continue case accruals, enrolling an additional 1000 AA women with breast cancer in CBCS and 1000 cases in WCHS and ascertainment of additional cases in BWHS and MEC, for a final sample size of more than 5,500 cases and 5,500 controls with DNA, providing sufficient power to conduct subtype analyses. Importantly, we will collect tumor tissue blocks from participants in the WCHS, CBCS and BWHS and, in collaboration with Core C, use immunohistochemistry (IHC) to identify breast cancer subtypes. This will allow us to pursue several hypotheses regarding the etiology of early aggressive breast cancer in AA women in the context of 4 independent, but interacting, projects. The success of the 4 scientific projects in this Program relies upon the successful activities of this proposed Core, to accrue and interview additional cases and to retrieve the tumor tissue blocks from the hospitals where participants in CBCS, WCHS and BWHS received their surgery. We have experience in these endeavors at each of our institutions, and the experiences of CBCS and WCHS in block collection will inform our efforts for BWHS through Core B. The specific aims of this Core are to: 1) Conduct data collection (case ascertainment, contact with physicians and patients, interviews, DNA collection) in the WCHS and CBCS. Conduct collection of saliva samples from new breast cancer cases in the BWHS;and 2) Request, collect, and process tissue blocks and pathology reports for WCHS, CBCS and BWHS, using a unified systematic approach for all sites. This Core is essential for increasing the number of breast cancer cases available for use in all four projects of this POI, and for collection of tumor blocks in a coordinated fashion so that we can characteristic breast cancer subtypes and examine genetic and non-genetic risk factors for early, aggressive breast cancer.